Analysis of an ancient meteorite suggests that rocky planets both near and distant from the sun may have formed at the same ...

Astronomers are closing in on one of the most tantalizing possibilities in planetary science, evidence that a previously unknown world may be lurking in the outer reaches of the solar system. The ...

What can rocky planets orbiting in the outer parts of a solar system teach scientists about planetary formation and evolution ...

A group of astronomers has found a solar system 116 light-years from Earth that seems to challenge current theories about how ...

An international team of astronomers has discovered a distant planetary system that challenges long-standing theories of how planets form. Across our galaxy, astronomers routinely observe a ...

An artist's impression of the planetary system surrounding LHS 1903, a small red dwarf star cooler and dimmer than our Sun. (European Space Agency) (CN) — For decades, astronomers thought they had ...

In the remote outer reaches of planetary systems, far beyond the orbit of known planets, enormous and mysterious worlds silently loop around their stars. Some drift as far as 10,000 times the distance ...

A new paper hypothesizes that there could be a Mars-sized object on the outskirts of the Kuiper Belt. If true, this would be distinct from the hypothesized Planet 9. Share on Facebook (opens in a new ...

An object eight times the mass of Jupiter may have swooped around the sun, coming superclose to Mars' present-day orbit before shoving four of the solar system's planets onto a different course. When ...